forked from pool/systemd
157 lines
6.7 KiB
Diff
157 lines
6.7 KiB
Diff
Simply writing /var/lib/systemd/random-seed back to /dev/(u)random does not
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increase the entropy bit count. Therefore use the RNDADDENTROPY ioctl to
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write back the bytes and increase the entropy bit counter.
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Related to bnc#892096
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---
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src/random-seed/random-seed.c | 71 ++++++++++++++++++++++++++++++++++++------
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1 file changed, 61 insertions(+), 10 deletions(-)
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Index: systemd-221/src/random-seed/random-seed.c
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===================================================================
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--- systemd-221.orig/src/random-seed/random-seed.c
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+++ systemd-221/src/random-seed/random-seed.c
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@@ -22,7 +22,9 @@
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#include <unistd.h>
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#include <fcntl.h>
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#include <errno.h>
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+#include <linux/random.h>
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#include <string.h>
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+#include <sys/ioctl.h>
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#include <sys/stat.h>
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#include "log.h"
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@@ -32,8 +34,8 @@
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#define POOL_SIZE_MIN 512
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int main(int argc, char *argv[]) {
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- _cleanup_close_ int seed_fd = -1, random_fd = -1;
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- _cleanup_free_ void* buf = NULL;
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+ _cleanup_close_ int seed_fd = -1, random_fd = -1, entropy_fd = -1;
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+ _cleanup_free_ struct rand_pool_info *entropy = NULL;
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size_t buf_size = 0;
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ssize_t k;
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int r;
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@@ -65,11 +67,12 @@ int main(int argc, char *argv[]) {
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if (buf_size <= POOL_SIZE_MIN)
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buf_size = POOL_SIZE_MIN;
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- buf = malloc(buf_size);
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- if (!buf) {
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+ entropy = (struct rand_pool_info*) malloc(sizeof(struct rand_pool_info) + buf_size);
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+ if (!entropy) {
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r = log_oom();
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goto finish;
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}
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+ entropy->buf_size = (typeof(entropy->buf_size)) buf_size;
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r = mkdir_parents_label(RANDOM_SEED, 0755);
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if (r < 0) {
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@@ -83,6 +86,23 @@ int main(int argc, char *argv[]) {
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if (streq(argv[1], "load")) {
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+ entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_RDONLY|O_CLOEXEC|O_NOCTTY, 0600);
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+ if (entropy_fd < 0) {
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+ entropy->entropy_count = 0;
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+ if (errno != ENOENT) {
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+ log_error("Failed to open " RANDOM_SEED "/entropy_count: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ } else {
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+ r = read(entropy_fd, &entropy->entropy_count, sizeof(entropy->entropy_count));
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+ if (r < 0) {
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+ log_error("Failed to read entropy count file: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ }
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+
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seed_fd = open(RANDOM_SEED, O_RDWR|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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if (seed_fd < 0) {
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seed_fd = open(RANDOM_SEED, O_RDONLY|O_CLOEXEC|O_NOCTTY);
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@@ -103,7 +123,7 @@ int main(int argc, char *argv[]) {
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}
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}
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- k = loop_read(seed_fd, buf, buf_size, false);
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+ k = loop_read(seed_fd, entropy->buf, (size_t) entropy->buf_size, false);
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if (k < 0)
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r = log_error_errno(k, "Failed to read seed from " RANDOM_SEED ": %m");
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else if (k == 0)
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@@ -111,13 +131,29 @@ int main(int argc, char *argv[]) {
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else {
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(void) lseek(seed_fd, 0, SEEK_SET);
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- r = loop_write(random_fd, buf, (size_t) k, false);
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- if (r < 0)
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- log_error_errno(r, "Failed to write seed to /dev/urandom: %m");
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+ if (entropy->entropy_count && (size_t)k == (size_t)entropy->buf_size) {
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+ r = ioctl(random_fd, RNDADDENTROPY, entropy);
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+ if (r < 0) {
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+ log_error_errno(errno, "Failed to write seed to /dev/urandom: %m");
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+ r = -errno;
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+ }
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+ } else {
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+ r = loop_write(random_fd, entropy->buf, (size_t) k, false);
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+ if (r < 0)
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+ log_error_errno(r, "Failed to write seed to /dev/urandom: %m");
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+ }
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}
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} else if (streq(argv[1], "save")) {
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+ /* Read available entropy count, if possible */
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+ f = fopen("/proc/sys/kernel/random/entropy_avail", "re");
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+ if (f) {
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+ if (fscanf(f, "%d", &entropy->entropy_count) < 0)
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+ entropy->entropy_count = 0;
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+ fclose(f);
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+ }
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+
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seed_fd = open(RANDOM_SEED, O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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if (seed_fd < 0) {
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r = log_error_errno(errno, "Failed to open " RANDOM_SEED ": %m");
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@@ -130,6 +166,21 @@ int main(int argc, char *argv[]) {
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goto finish;
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}
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+ if (entropy->entropy_count) {
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+ entropy_fd = open(RANDOM_SEED_DIR "entropy_count", O_WRONLY|O_CLOEXEC|O_NOCTTY|O_CREAT, 0600);
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+ if (seed_fd < 0) {
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+ log_error("Failed to open " RANDOM_SEED_DIR "entropy_count: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ r = write(entropy_fd, &entropy->entropy_count, sizeof(entropy->entropy_count));
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+ if (r < 0) {
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+ log_error("Failed to write entropy count file: %m");
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+ r = -errno;
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+ goto finish;
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+ }
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+ }
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+
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} else {
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log_error("Unknown verb '%s'.", argv[1]);
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r = -EINVAL;
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@@ -144,7 +195,7 @@ int main(int argc, char *argv[]) {
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(void) fchmod(seed_fd, 0600);
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(void) fchown(seed_fd, 0, 0);
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- k = loop_read(random_fd, buf, buf_size, false);
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+ k = loop_read(random_fd, entropy->buf, (size_t) entropy->buf_size, false);
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if (k < 0) {
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r = log_error_errno(k, "Failed to read new seed from /dev/urandom: %m");
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goto finish;
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@@ -155,7 +206,7 @@ int main(int argc, char *argv[]) {
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goto finish;
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}
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- r = loop_write(seed_fd, buf, (size_t) k, false);
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+ r = loop_write(seed_fd, entropy->buf, (size_t) k, false);
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if (r < 0)
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log_error_errno(r, "Failed to write new random seed file: %m");
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}
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